Proper weighting and trim
First Employee May 18, 2016
What do you look like underwater? Some divers walk across the bottom, some use their hands and fins to swim, and some kick like they are riding a bicycle(don’t do any of that). I have heard some instructors tell students that a divers underwater orientation does not matter as long as you are breathing. However, I want to share with you today a few things that will help you become more stable underwater and look great while doing it.
Check out these pictures below. Which diver looks like they are more streamlined, stable, and will have the least amount of resistance while moving underwater.
If you chose the horizontal diver, your right. This is called being trimmed out. This divers orientation creates the least amount of drag underwater. On the surface of Earth, we walk upright because it is the most efficient method of travel. However, this is not efficient underwater. When we dive underwater we are in a totally different environment like an astronaut in space. Like astronauts, divers have to practice how to position themselves and move in a foreign environment. Underwater, the most effect way to move is in the horizontal trim position.
Being properly weighted is the first step to getting in trim. Where you place weight on your bcd has a direct effect on how your body will be positioned while diving. Placing all the of the weight toward the divers waist or butt can cause a head up - butt down position. Placing all the weight towards your shoulders can cause a head down - butt up position. Because everyone's body is different, weight positioning will vary to each diver.
The first thing to do is to get the right amount of weight on you. You want to check for proper weighting with a tank at 500psi. This is because your tank loses weight and becomes more positively buoyant as you breathe it down. Checking your weighting with 500psi left in the tank will ensure that your are neutrally buoyant at the end of your dive. Doing this with a full tank on will make you positively buoyant at the end of your dive and you will have difficulties staying down during your safety stop.
Here is how to find the right amount of weight.
With a dive buddy helping, (keep regulator in your mouth during this incase you sink)
- Take your tank down to 500psi
- At the surface, deflate your BCD and hold a normal breath of air in your lungs.
- If you are weighted properly, you will float at or near eye level. If you release the air from you lungs you should begin to sink.
- If you are overweighted, your will sink. Remove some weight and repeat step 2.
- If you are underweighted, you will float above eye level. Add weight and repeat step 2.
If you have been diving over/under weighted, you will immediately feel the difference and the freedom of diving neutrally buoyant. Its easier to control yourself, you will consume less air, you will slip through the water with much less effort, and tons of other benefits will come by diving neutral.
Now, being weighted properly does not necessarily mean that your diving in the horizontal trim position. This has to do with weight placement, practice and discipline. Placing all the of the weight toward the divers waist or butt can cause a head up - butt down position. Placing all the weight towards your shoulders can cause a head down - butt up position. Use your dive buddy to help move weight around to help you achieve the horizontal position. You shouldn’t have to contort your back to achieve this position. You do want to arch your back a bit, but it shouldn't be tiresome or painful. If your having to twist your body to stay horizontal, you need to work on weight placement. Stay still while hovering and see if you lean to one side or the other. If so, make adjustment to weight placement. Take pictures and judge yourself against the pictures above. Keep your legs bent up at a 90 degree angle like in the picture above. Make a conscious effort to not kick up the bottom. Kicking up the bottom is a great way to show other divers your skill level. They will probably not be happy that you trashed the visibility. Another thing to consider is that kicking up the bottom does damage and can kill coral and other delicate marine life.
Keep practicing. Practice makes progress! Also, consider taking an advanced buoyancy course. I can help you get trimmed out and diving like a pro.
